The invention relates to a method for testing elongated objects, optionally having a non-circular cross-section by means of at least one test coil through which passes a test object and having a predetermined coil plane passage cross-section, in particular an eddy current coil, as well as to a testing apparatus for performing the said method with at least one test coil having a predetermined coil plane passage cross-section and optionally a reception member for receiving the test coil. The invention more particularly relates to the problem of non-destructively and substantially uninterruptedly testing for surface defects metallic semifinished products having a non-circular cross-section.